Evaluation of methods for sizing of colloidal radiopharmaceuticals

Many different quality control methods have been proposed for characterization of colloidal radiopharmaceuticals, as particle size seems to be of importance for the resulting biological distribution. Membrane filtration techniques using polycarbonate sheet filters (Nuclepore) is a simple technique. For a number of products good correlation was obtained to particle sizes measured by photon correlation spectroscopy (Nanosizer). For several preparations an increase in particle size with time was observed.